Godot is a powerful cross-platform game engine
Enables Roblox developers to use professional software tools
A simple and easy-to-use library to enjoy videogames programming
Real Time Strategy game engine supporting early Westwood classics
Open game and rendering engine packed into a JavaScript framework
Desktop/Android/HTML5/iOS Java game development framework
One framework for creating powerful cross-platform games
Open Source MMORPG Framework
Fast and lightweight JavaScript game engine built on WebGL and glTF
Open source HTML5 game framework that offers WebGL and Canvas
ThinkPHP Framework
lua dev plugin for unreal engine 4 or 5
Open source library for N64 development
Open source library for creative expression on the web, desktop, etc.
Self-hosted CMS platform based on the Laravel PHP Framework
A game framework written with osu! in mind.
You can make it - Open Source MMORPG Platform
Gideros Release version
CTFs as you need them
Arianne is an engine to develop multiplayer online games like Stendhal
TX Library is a tiny graphics library for Win32 written in C++.
INSTEAD - Simple Text Adventure Interpreter.
Game engine supporting many 3D/2D formats and graphic effects
Orx: Portable Game Engine
Old-school 2D game engine